New installer (setuptools)

some small bugs corrected since 1.0, inparticular:

• fixed an error which affected number of sigma calculation (significance): only affect large values, and significance below or equal to 4 remain unchanged
• improved multiprocessing feedback (completion bar)
• New installer getting rid of "setup.py" file

stable for python 2.7 and 3.7

v1.0

version 1.0 for Python 3